In the 1979 film When a Stranger Calls, the horror is provided when police tell a young babysitter that the harassing phone calls she has been receiving are coming from inside the house. It was terrifying for viewers because the intruder had already gotten inside, and was presumably free to wreak whatever havoc he wanted, unimpeded by locked doors or other perimeter defenses. In 2016, that same level of fear is being rightfully felt towards a similar danger in cybersecurity: the insider threat.

An entire industry has sprung up to provide a defense against insider threats. We tested products from Fortscale, Avanan, and PFU Systems, with each one concentrating on a different aspect of the problem.